Method for operating a dirt stop surface, dirt stop surface unit and dirt stop surface assembled therefrom

ABSTRACT

The invention relates to a method for cleaning of indoor or outdoor areas by operating a dirt stop surface, comprising the steps of dividing the dirt stop surface ( 1 ) into surface units ( 4 ), dispensing a fluid flow on the surface to be cleaned, while the proximity of the surface to be cleaned is sensed separately for each surface unit ( 4 ), and the fluid is dispensed from the surface units ( 4 ) of the dirt stop surface in a selective manner such that only the surface units ( 4 ) in the proximity of which the presence of the surface to be cleaned has been sensed are applied for dispensing the fluid. The invention relates further to a dirt stop surface unit and a dirt stop surface assembled therefrom that is capable of carrying out the method.

The invention relates to a method for cleaning of indoor or outdoorareas by operating a dirt stop surface, and also to a dirt stop surfaceunit and a dirt stop surface assembled therefrom that is capable ofcarrying out the method.

Cleanliness of areas is usually provided by cleaning, which involvescontinuous or regular removal of contaminants and dirt. However,cleaning is uneconomical when no contamination is present, andeconomical cleaning may result in unacceptable levels of contamination,necessitating a compromise between the frequency of cleaning and thelevel of contamination that will vary in time and space but will not bereduced to zero.

Compared to cleaning an area, it is less expensive and way easier tocapture contaminants before they could enter the area to be kept clean,usually directly at the entryways for people and goods traffic.

70-80 percent of contaminants are carried in buildings on the shoes ofpeople entering them. Contaminants first accumulate on the ground, butdust and other contaminants may eventually accumulate everywhere, makingcleaning a troublesome and costly undertaking (see “Tiszta TérTechnológia” Épu{umlaut over (l)}ettisztítási Szakmagazin,http://tisztatertechnologia.hu)

Therefore, especially at building entrances having heavy traffic, dirtstop mat systems are applied, such as for instance the productsbelonging to the Nomad™ dirt stop product family made by 3M. Dirt stopsolutions for vehicle traffic areas utilising brush devices are alsoknown. Such a solution is disclosed for instance in the document EP2240066 (A2). However, these mechanical devices themselves requireregular cleaning since, depending on the load of traffic, they becomesaturated sooner or later, which deteriorates cleaning efficiency incase accumulated dirt or dust are not removed. Known solutions forcleaning the wheels and tires of vehicles include for instance a devicedescribed in the document U.S. Pat. No. 6,561,201 that contains anelongated tank and water sprays directed to the wheels (in a mannersimilar to car wash devices). The applicability of such solutions may belimited by their large space demand and also by the relatively largewater amount that is carried off by the vehicle leaving the apparatus.Another known solution for preventing contaminants from being carriedinto areas to be kept clean is a disposable sticky mat applied amongothers at doors of clean rooms (see e.g. www.stickystep.com). To providesustained cleaning capability, the topmost sheet has to be removed bypulling it off from the multi-sheet mat when the sheet becomes saturatedwith contaminants.

The objective of the present invention is to provide a method andapparatus for preventing contaminants from entering an area to be keptclean that quickly and effectively cleans contaminating surfaces(wheels, shoe soles) of people and vehicles crossing the line dividingclean and contaminated areas without disturbing pedestrian or motorisedtraffic. A further objective of the invention is to provide ahigh-efficiency cleaning method and apparatus based on the principle ofpreventive action that may be adapted for many different fields ofapplication such that it may prevent the spreading of contamination andreduce the need for subsequent cleaning, and that may be operated in asustained and economical manner without human attendance in case ofheavy or varying intensity traffic. The inventive apparatus should below maintenance, should have self-cleaning capability, aestheticappearance, and long operating life. It should be capable of operationboth indoors and outdoors under diverse weather and environmentalconditions (in dry, humid, wet, or freezing and snowy weather as well asin dusty, dirty, greasy, sticky, chemical-loaded environments). Themethod and apparatus should be capable of operation in a widetemperature range, and should also allow the application of chemicalagents, detergents, disinfectants and perfumes.

The invention is based on the recognition that by producing an activedirt stop surface, particularly one dispensing a cleaning fluid thatoperates only at the time and location of its contact with the surfaceto be cleaned it is possible to create a cleaning machine that cleans ina preventive manner, before contamination would occur.

The inventive solution is defined in the independent claims, while thepreferred embodiments are described in the dependent claims.

The invention will be explained below with reference to the accompanyingdrawings, where

FIG. 1. illustrates the most frequently occurring contact surface types,such as the surfaces of vehicle wheels and shoe soles contacting theground,

FIG. 2 shows the schematic view of the surfaces to be cleaned inrelation to a dirt stop surface divided into surface units,

FIG. 3 shows the spatial view of the base body of a surface unit of thedirt stop surface from above,

FIG. 4 is the spatial view of the base body of FIG. 3 shown from below,

FIG. 5 is the detail view of the base body according to FIG. 3 showingthe valves,

FIG. 6 is the lateral sectional view of the base body shown in FIG. 5,

FIG. 7 shows the partially sectioned spatial view of an assembled valveunit from above,

FIG. 8 shows the spatial view of the intermediate body of a surface unitfrom above,

FIG. 9 is the spatial view of the intermediate body of FIG. 8 shown frombelow,

FIG. 10 is the spatial view of the upper body of a surface unit shownfrom below,

FIG. 11 is the spatial view of the upper body of FIG. 8 shown fromabove,

FIG. 12 is the spatial detail view of an assembled dirt stop surface,shown from above, and

FIG. 13 shows the exploded spatial view of an alternative embodiment ofthe surface unit.

According to the present invention the dirt stop surface 1 is dividedinto surface units 4 that are able to sense the presence of a surface tobe cleaned, such as the contact surface of a vehicle wheel 2 or a shoesole 3, in their proximity, with the dirt stop surface 1 performingcleaning action by dispensing cleaning fluid on the surfaces to becleaned from those surface units that are substantially fully covered bythe surfaces to be cleaned. The smaller the size of individual surfaceunits, the better the outline of the surface to be cleaned may betraced, and thus the better the “resolution” of the “mapping” becomes.For the sake of clarity in FIG. 2 the “activated” surface units 4(indicated by dots) that are performing cleaning action on wheel andshoe sole surfaces are shown exaggerated in size. Since the dirt stopsurface 1 according to the present invention expediently has uniformcleaning efficiency over the entirety of the surface, the path of wheels6 or pedestrians may lead to any direction. In principle, any knownsolution may be applied for sensing the presence of the surface to becleaned, and also many different solutions may be applicable forselectively dispensing the cleaning fluid. To show the specificadvantages of the inventive solution, details of the present inventionare explained in relation to a preferred embodiment that utilisesmechanical means for proximity sensing.

FIG. 6 shows an assembled valve unit of which the upper surface isconstituted by a surface unit 4. The valve unit is adapted fordispensing cleaning fluid, expediently a liquid and preferably water, ona surface to be cleaned when the presence of such a surface is detectedabove it. The presence of the surface to be cleaned is detected byelements—pins 15—protruding from the surface unit 4 and adapted to getdepressed under force. When all pins—in this case, all four pins—aredepressed, cleaning fluid, for instance water, is dispensed from thesurface area bounded by the pins on the surface to be cleaned that islocated directly above the surface unit. The valve unit consists of abase body 10, an intermediate body 21, and an upper body 22 arrangedabove one another. Water enters the base body 10, shown from above inFIG. 3, through an inlet opening 11, and may flow as far as the middleof the base body 10 in a flow channel 13 along the flow path 28 shown indashed line in the drawing, and may leave the base body 10 in an upwarddirection. Valve ducts 14 are disposed in the flow channel 13, withcylindrical pins 15 being arranged in the valve ducts 14. Functioning asvalves, the pins 15 may shut off or open the flow channel 13. In FIG. 5the left pin 15 is in closed position, while the right pin 15 is in openposition, because if the groove 17 of the pin 15 is located in the flowchannel 13 (otherwise blocked by the intermediate body 21), it frees upthe path of the flow. FIG. 6 shows this arrangement in sectional viewalso showing the stop surfaces 19 adapted for limiting the displacementof the pins 15. The pins 15 are expediently pushed in their upperterminal position by a resilient element that in the embodiment shown inthe drawings is implemented as an air spring 40. The pins may bedepressed as far as the tread surface 7 under the force exerted on outerend 18 by a shoe sole or a wheel to be cleaned. The valves configuredaccording to FIGS. 5-6 utilising pins 15 are connected in serialconnection, implying that the valve unit formed by the valves will beopen only when all the valves are in their open position. The undersideof the intermediate body 21 is sealedly seated on the base body 10. Aflow path 28, shown in dashed lines in FIG. 9, is disposed on theunderside of the intermediate body 21. The flow ascends to the undersideof the upper body 22 that is sealedly seated on the upper side of theintermediate body (FIG. 9) through an ascending vent 24. FIG. 10illustrates the underside of the upper body 22, showing the openings 25adapted for dispensing the cleaning fluid. The openings 25 open on theknurled tread surface 7 forming the upper side of the upper body 22. Theabove described elements of the valve unit are retained by screws 23disposed in through holes 27, with a screw disposed in the hole in themiddle of the base body 10 being applied only for retaining the basebody, and thereby remaining in place when the valve unit isdisassembled. The fluid inlets and mechanical support necessary for theoperation of the valve unit are provided by base units 32. Spentcleaning fluid, flowing back between surface units 4 (that is, betweenvalve units) may be drained off also utilising the base units 32 thatare arranged with spacings between them (FIG. 12). Sufficient rigidityof the assembled dirt stop surface 1 is provided by a foundation plate31 and a base plate 33 between which the base units 32 are sandwiched.The valve units constituting the surface units 4 are mounted on the baseplate 33 such that they are bounded along the sides of the dirt stopsurface 1 by upper bounding pieces 35. In a similar manner, the baseunits 32 are bounded laterally by bottom bounding pieces 34 alsoproviding the inlet and draining of the fluid, and are covered by coverplates 36.

In addition to the above described elements necessary for performing thebasic function of the dirt stop assembly, that is, detecting thepresence of a surface to be cleaned and dispensing cleaning fluidthereon, the invention is capable of performing other supplementaryfunctions:

-   -   Cleaning and/or drying of the surfaces to be cleaned may be        performed by means of compressed air blowing. To achieve that,        compressed air fed under the pin 15, originally functioning as        an air spring 40, is fed through ducts 41, 42 in a buffer space        43 between the base body 10 and the intermediate body 21 whence        it flows out at the surface through openings 44. The timing of        compressed air blowing may be set by adjusting the relative        position of duct 42 and the buffer space 43.    -   Self-cleaning may be performed by introducing cleaning liquid        through one or more inlet openings 45 to the base body 10. The        cleaning fluid flows through distribution ducts 46 disposed        between the base body 10 and the intermediate body 21, and is        fed through outlet ducts 47 to the drain channel disposed        between the valve units constituting the surface units 4, from        where it may wash off contaminants. In an arrangement comprising        air springs, the tread surface 26 may be cleaned at a reduced        fluid pressure by depressurizing the air springs.    -   In case of applications where there is a danger of frost, the        assembly may be tempered by for instance introducing tempering        liquid along one of the corner screws 23. Following path 50        indicated in FIG. 4 by a dotted line, the tempering liquid flows        through flow space 48, flowing alongside the screws 23 through        holes 27 into flow space 49 shown in FIG. 8, and then flowing        through the other side of the flow space 49 downward to the base        body 10 from where it may be drained off.

FIG. 13 shows another conceivable embodiment of the valve unitsconstituting the surface units 4, where a larger surface area may becovered with openings 25 because the pins 15 are arranged in the cornersof the surface unit 4. Otherwise the arrangement is similar to the firstembodiment described above. The retainer screw arranged in the middle ofthe base body 10 is also clearly shown in the drawing.

The solution according to the invention, of which the preferredembodiments are defined in the accompanying Claims, is capable offulfilling the objective of the invention.

Applying basic building blocks (valve groups, valve units, adapterelements, etc.) the cleaning system may be expanded into an automateddirt stop surface of any size and shape.

The utility system (cleaning and rinsing fluid supply, compressed airsupply, tempering fluid supply, drain means for spent fluids) and theautomated control system adapted for controlling it (controlled valves,active and passive flow control elements, pressure and flow sensors,heating elements, fluid mixers, pumps, etc.), as well as theprogrammable central unit (microcontroller, PLC) performing systemsupervision together provide that the apparatus is operated safely, andthat the entire cleaning process is carried out in a coordinated andefficient manner.

The high-resolution detection system of the cleaning surface of theapparatus functionally performs a “sampling” of the shape of thesurfaces to be cleaned passing over it. Detecting the shape and positionof the shoe soles and tires it is capable of controlling the entirecleaning process that is promptly started as the presence of the surfaceto be cleaned is detected, and is completed in a few seconds applyingthorough, active water-based cleaning. The entire surface of theautomated dirt stop apparatus is always in stand-by state, ready toperform cleaning action. Cleaning may be performed at any point of thesurface of the apparatus with uniform efficiency and speed, but isinitiated only at those surface units that are covered by the surfacesto be cleaned, and these units remain activated only as long as thesurface to be cleaned is in their immediate proximity. During thecleaning process nothing else but the contacting surfaces get wet.

The automation scheme of the apparatus allows a wide range of possibleapplications. Advantages of the inventive apparatus include theprogrammable dispensing of solvents, disinfectants, and perfumes, thecapability of cleaning utilising cold, warm, and hot water, a fullyautomated event-driven operation, effective multi-stage self cleaning(programmable cycles), and optimal water use.

Further advantages are improved environmental compliance through anoptionally available water cleaning and recirculation system,energy-saving and safe operation, aesthetically pleasing appearance,simple operation, and exceptionally long service life. The apparatus ishighly customisable in a wide range as far as mechanical and chemicalendurance are concerned. It may be freely adapted in shape, and is ableto dry cleaned surfaces. It may be implemented in portable or stationaryform, has low maintenance costs, and in case of any malfunction it maybe serviced simply and quickly.

List of reference numerals 1 dirt stop surface 4 surface unit 6 wheel 7tread surface 10 base body 11 inlet opening 13 flow channel 14 valveduct 15 pin 17 groove 18 outer end 19 stop surface 21 intermediate body22 upper body 23 screw 24 ascending vent 25 opening 26 tread surface 27hole 28 flow path 31 foundation plate 32 base unit 33 base plate 34bottom bounding piece 35 upper bounding piece 36 cover plate 40 airspring 41 duct 42 duct 43 buffer space 44 opening 45 inlet opening 46distribution duct 47 outlet duct 48 flow space 49 flows space 50 path

1. Method for operating a dirt stop surface, comprising the steps of:dividing the dirt stop surface into surface units, dispensing a fluid toflow on a surface to be cleaned, where the fluid is adapted for removingcontamination from the surface to be cleaned, and draining off the fluidfrom the surface to be cleaned, characterised by that the proximity ofthe surface to be cleaned is sensed separately for each surface unit,and the fluid is dispensed from the surface units of the dirt stopsurface in a selective manner such that only the surface units in theproximity of which the presence of the surface to be cleaned has beensensed are dispensing the fluid.
 2. The method according to claim 1,characterised by that at least three sensors are applied for eachsurface unit, one or more openings are arranged in the surface unit inan area bounded by straight lines connecting adjacent sensors locatedclosest to an edge of the surface unit, and fluid is dispensed from anoutlet opening when the proximity of the surface to be cleaned isindicated simultaneously by all sensors of the given surface unit. 3.The method according to claim 2, characterised by that the sensors areimplemented as mechanical sensor means, and the flow of the fluid iscontrolled applying valves arranged in serial connection.
 4. The methodaccording to claim 3, characterised by that the same element is appliedas sensor and as one of the valves controlling the flow of the fluid,and said sensor and valve element is expediently implemented as acylindrical pin adapted to get displaced in a direction perpendicular tothe surface unit as the element is depressed by surface to be cleaned.5. The method according to claim 4, characterised by that a resilientelement is applied for retaining the pins in a normal position, where intheir normal position the pins protrude from the surface of the surfaceunit, and the pins are returned from their depressed position to thenormal position by the resilient element.
 6. The method according toclaim 5, characterised by that compressed air is utilised as theresilient element.
 7. The method according to claim 1, characterised bythat synchronised with the dispensing of the fluid, compressed air isblown on the surface to be cleaned and thereby cleaning and dryingaction is performed on the surface to be cleaned.
 8. The methodaccording to claim 1, characterised by that a liquid, expediently water,is utilised as cleaning fluid adapted to remove contamination from thesurface to be cleaned, and the dirt stop surface is cleaned utilising abuilt-in system that is operable separately, where cleaning isexpediently performed utilising water rinsing, and to control atemperature of the dirt stop surface, a heating liquid, preferablywater, is circulated in the dirt stop surface units.
 9. The methodaccording to claim 1, characterised by that the drained off cleaningfluid is treated in a closed circuit.
 10. Dirt stop surface unitcomprising a front face constituting a tread surface, with sensor meansbeing disposed corresponding to the surface unit, characterised by thatthe surface unit has at least one outlet opening adapted for dispensingcleaning fluid, a shut-off element is connected to the surface unit, theshut-off element being adapted for controlling the dispensing of thefluid, at least three sensors are disposed on the surface unit, and theshut-off element adapted to control the dispensing of cleaning fluid isarranged to be in operating connection with the sensor.
 11. The surfaceunit according to claim 10, characterised by that the opening oropenings are arranged in the surface unit in an area bounded by straightlines connecting adjacent sensors located closest to an edge of thesurface unit.
 12. The surface unit according to claim 10, characterisedby that mechanical sensor means are arranged in the tread surface of thesurface unit, where the sensors are implemented as preferablycylindrical pins adapted to get displaced in a direction substantiallyperpendicular to the tread surface, with a resilient element, preferablyan air spring being disposed under the cylindrical pins, where theresilient element is adapted to retain the pins in, or return them to, anormal position.
 13. The surface unit according to claim 12characterised by that a flow channel is disposed under the treadsurface, the flow channel being arranged in a plane substantiallyparallel with the tread surface, where the pins are arranged to protrudein the flow channel such that in the normal position of a pin the flowchannel is shut off by the pin and in the position where the pin isdepressed to the tread surface the flow channel is open, where in itsnormal position the pin protrudes from the tread surface.
 14. Thesurface unit according to claim 13, characterised by that the pinsprotruding in the flow channel are arranged in serial connection. 15.The surface unit according to claim 12, characterised by that the pinsare adapted to function both as one of the sensors and the shut-offelement.
 16. The surface unit according to claim 10, characterised bythat it also comprises at least one opening adapted for dispensing agaseous cleaning and/or blowing fluid, expediently compressed air. 17.Dirt stop surface assembled from surface units according to claim 10,characterised by that the dirt stop surface has base units adapted forretaining the surface units, for supplying fluid to the surface units,and for collecting the fluid dispensed, where the base units areconfigured such that they can be integrated along contact surfaces toproduce the dirt stop surface of arbitrary size.